In U.S. Pat. No. 3,243,211, there are disclosed numerous heat recoverable articles including generally tubular heat-shrinkable articles having fusible inserts of various types. Examples of fusible inserts are thermoplastic polymeric materials and meltable inorganic materials, for example solder, and numerous devices constructed in accordance with the above patent, the disclosure of which is incorporated by reference herein, are available commercially.
Typical of such devices are a heat-shrinkable tube having disposed within it a ring of solder, and a similarly equipped tube also having at or near each end a ring of fusible polymeric material. When either of the devices is installed by heat-shrinking over, for example, a pair of conductors to be joined, the tube shrinks and the solder melts, simultaneously forming a secure electrical connection between the conductors and completing the insulation of the joint. If the article is provided with polymeric rings, these melt and form an effective means of preventing moisture ingress and reinforce the shrinking ends of the tube in preventing escape of solder from the desired area.
Commercially available articles constructed as above are, of course, only able to join a single pair of conductors within each tubular sleeve. When a plurality of pairs of conductors are to be connected, they are each connected within their own individual sleeve.
There are occasions, however, where it is desirable that a single sleeve should be used to encapsulate the junction between two or more pairs of conductors. Such an arrangement may save space in confined situations and it may allow shorter installation time. More significantly, however, it may be electrically more satisfactory in connecting conductors to be used for high frequency applications, since it allows the impedence of the junction to approach more closely that of the cable. For example, certain types of telephone cable for use in pulse code modulation transmission contain four conductors, arranged, and dimensioned to have an impedence of 75 ohm, and the nearer the impedence of the junction to this value the better.
Accordingly, it is an object of this invention to provide improved means for encapsulating a plurality of elongate substrates.
Another object of this invention is to provide means for making electrical connections between plural pairs of electrical conductors that also isolates individual pairs.
These and other objects will be apparent to those skilled in the art in view of the following description of the invention.